MP3 is one of several audio parts in the MPEG technology. MP3 is an audio file format with the file extension name of MP3 made using an audio data coding technology and has the capacity of compressing existing data by about {fraction (1/12)}without noticeable loss of sound quality. Accordingly, it is suitable for transmitting and receiving an audio file using a limited transmission line.
In general, an MP3 file can be heard by inserting an earphone into an MP3 player such as that shown in FIG. 1. In FIG. 1, reference numeral 10 denote function buttons for play, rewind and record; reference numeral 12 denotes an LCD display panel for displaying the status such as play or rewind; and reference numeral 14 denotes an earphone jack.
In the MP3 player shown in FIG. 1, MP3-coded music can be reproduced by inserting an earphone into the earphone jack 14 and pressing the play button.
However, to listen to the MP3 music through an audio cassette player without an earphone, a cassette tape for an audio cassette tape interface is connected to the earphone jack 14 of the MP3 player and the cassette tape is inserted into an audio cassette deck, as shown in FIG. 2. The cassette tape of FIG. 2 has a structure in which audio signals are magnetized by a head (not shown) and the magnetized audio signals are applied to a head of the audio cassette deck. The audio cassette deck converts the input magnetized signals to electric audio signals and outputs the converted signals to speakers.
However, such method is inconvenient in that the above additional cassette tape for interfacing is needed to listen to MP3 music through an audio cassette player. Thus, an apparatus which enables listening of various digital audio data including MP3 music through an audio cassette player such as a car audio cassette player is needed.